Patient Body Mass Index is an Independent Predictor of 30-Day Hospital Readmission After Elective Spine Surgery

Abstract

Background: Hospital readmission within 30 days of index surgery is receiving increased scrutiny as an indicator of poor quality of care. Reducing readmissions achieves the dual benefit of improving quality and reducing costs. With the growing prevalence of obesity, understanding its impact on 30-day unplanned readmissions and patients' perception of health status is important for appropriate risk stratification of patients. The aim of this study was to determine if obesity is an independent risk factor for unplanned 30-day readmissions after elective spine surgery.

Methods: The medical records of 500 patients (nonobese, n = 281; obese, n = 219) undergoing elective spine surgery at a major academic medical center were reviewed. Preoperative body mass index (BMI) was measured on all patients. BMI that was ≥30 kg/m² was classified as obese. Patient demographics, comorbidities, and postoperative complication rates were collected. The primary outcome investigated was unplanned all-cause 30-day hospital readmission. The association between preoperative obesity and 30-day readmission rate was assessed via multivariate logistic regression analysis.

Results: Baseline characteristics and operative variables and complication profiles were similar between both cohorts. Overall, 8.6% of patients were readmitted within 30 days of discharge; obese patients experienced a 2-fold increase in 30-day readmission rates (obese 12.33% vs. nonobese 5.69%, P = 0.01). In a multivariate logistic regression analysis, preoperative obesity (BMI ≥30 kg/m²) was found to be an independent predictor of 30-day readmission after elective spine surgery (P = 0.001).

Conclusions: Preoperative obesity is an independent risk factor for readmission within 30 days of discharge after elective spine surgery. In a cost-conscious health care climate, preoperative BMI can identify patients at risk for early unplanned hospital readmission.

Keywords: 30-Day readmission; BMI; Body mass index; Obesity; Spine; Surgery.